Apparatus and process for cleaning plants



May 24, M66

J. w. SWINK 3,252,466

APPARATUS AND PROCESS FOR CLEANING PLANTS Filed Sept. 10, 1963 2Sheets-Sheet 1 FIGURE l Receiving 2 3 7 k a e W I Predominaie HumidifierLoudmg Cleonlng Grading Grade V Grades 4 5J- Bundling and Tying 6Purchaser Inventor J. WOODROW SWINK May 2%, 166 J. w. SWINK APPARATUSAND PROCESS FOR CLEANING PLANTS 2 Sheets-Sheet 2 Filed Sept. 10, 1963 iQ WW Q m MEDQE Inventor J. WOODROW SWINK By jag-wt M Attorney UnitedStates Patent 3,252,466 APPARATUS AND PROCESS FOR CLEANING PLANTS JamesWoodrow Swink, Eflingham, S.C., assignor to Research Corporation, NewYork, N.Y., a non-profit corporation of New York Filed Sept. 10, 1963,Ser. No. 307,861 7 Claims. (Cl. 131-138) The present invention isbroadly concerned with an'improved process and apparatus for thecleaning and grading of tobacco plant leaves. The invention is moreparticularly concerned with an improved technique for processing curedtobacco leaves by the farmer or producer himself or tobacco leavesreceived by the processor in bulk form from the producer or themanufacturer. In accordance with the present process, foreign materialssuch as dirt, sand, string, feathers, etc., in cured tobacco areeffectively and efficiently removed from tobacco leaves before beingdelivered by the producer to the market or warehouse by a uniqueintegrated process and apparatus.

It is known in the art that one of the biggest and most vexing problemsof the tobacco industry is the effective removal of foreign materialswhich comprise sand, string,

, feathers, grit and the like that are closely associated with tobaccowhen the tobacco leaves are delivered to the processor or to the market.Many solutions and techniques have been proposed, but thus far theseproposals have not been economically elfective. Thus, to a great extent,manual cleaning techniques are still utilized.

These foreign materials are appreciable and, in many instances,approximate about of the total weight of the tobacco as it is purchased.vThus, one object of the present invention is to effectively andeconomically clean the tobacco when it comes directly from the curingbarn so as to reduce these foreign materials to substantially zero. Thiscleaning of the tobacco is secured by utilizing a plurality ofintegrated processing operations. Another object is the mechanicalgrading and tying or bundling of the tobacco so that a uniform bundle,bale or pile is delivered to the market, processor or manufacturer.

These integrated operations, in essence, comprise a receiving operation,a humidifier operation and a loadingcleaning-grading operation and atying or bundling operation. The particular adaptation of the presentinvention is to integrate the loading-cleaning-grading and tying orbundling operations into a plurality of stages by which substantiallyall of the undesirable materials or contaminants are effectively removedfrom the leaf tobacco in a very economical manner whereby the tobacco isproperly graded.

operation 1. The cured tobacco is received from the producer in bulkform and is not tied, but all the stem ends of the leaves are together.

After the tobacco has been received and handled at the receivingoperation 1, it is passed to a process humidify- 3,252,466 Patented May24, 1966 ing operation 2 where the moisture content of the tobacco israised and adjusted to the necessary level in order to get the tobaccoin order for the succeeding operations. Effective control is maintainedin order that the quality of the tobacco is not impaired by theintroduction of too little moisture or too much moisture. Generally themoisture content should be in the range from about 20 to 25%. Thetobacco is then normally passed to the loading-cleaning gradingoperation 3 wherein the same is graded into grades 1, 2, 3, and 4, asillustrated by the numeral 4. The graded tobacco is then passed intooperation 5 where the tobacco is bundled and tied prior to transportingthe tobacco to the ultimate purchaser 6. The predominant grade is passedto operation 7 and thence to the bundle and tying operation 5.

As is known in the art, the average number of grades of tobacco from onebarn of tobacco is four, but quite often there are only two grades.However, there is always one predominant grade comprising approximately60 or of the tobacco from the same curing.

Referring specifically to FIGURES 2a and 2b, three basic stages ofoperation 3 of FIGURE 1 are illustrated; namely, a separation stage 10,a cleaning stage 11, and a grading stage 12. FIGURE 2a is across-sectional view of the operation, while FIGURE 2b is a top view ofthe operation. It is to be noted that separation stage 10 comprises aplurality of operational zones. For example, separation stage 10comprises vibration zones 13, 14, and 15.

Thus, in the process, the tobacco leaves after removal from thehumidifying operation 2 of FIGURE 1 are manually loaded upon a wire meshconveyor belt 16 on a loading table 40. All the stems of the tobaccoleaves are placed perpendicular to the line of travel with all the stemends on the same side of the conveyor belt 16. This conveyor belt 16 inconjunction with other wire conveyor belts 17 and 18 will cause thetobacco to move progressively through the separation zone 10. Conveyorbelts 17 and 18 are mounted on supported tables 41 and 42 respectively.In accordance with the present process, all three belts 16, 17, and 18are vibrated. Furthermore, a distinct feature of the present inventionis that all of these belts move at progressively greater velocities. Forexample, if the velocity of vibrating conveyor belt 16 is V =A ft./sec.,then the velocity of conveyor belt 17 is V =V +K V and the velocity ofvibrating belt 18 will be V =V +K V where K is a multiplying constant.

Although the lengths of the respective conveying perforated belts 16, 17and 18 may be varied appreciably and may be of equivalent lengths, apreferred adaptation is to have belt 16 longer than belt 17 and belt 17longer than belt 18. 17 be 60 to of the length of belt 16, and that belt18 be 60 to 90% of the length of belt 17. Also, the lengths of thesebelts could be adjusted in inverse ratio to the velocity of therespective belts. By utilizing this technique, more efficient cleaningand grading of the tobacco is secured. Furthermore, the height ofvibrating belt 18 is below the height of vibrating belt 17 which, inturn, is below the height of vibrating belt 16. The difference in heightis in the range from about 1 to 6".

Also, the velocities of the respective belts may vary widely dependingupon various operating factions. However, it is generally preferred thatthe velocity in ft./ sec. of vibrating belt 16 be in the range fromabout 7 to 17,

Generally, it is preferred that the length of belt such as 12 ft./sec.,and the velocity of vibrating belt 17 be in the range from 9 to 19, suchas 14 ft./sec., and the velocity of vibrating belt 18 be in the rangefrom about 11 to 21, such as 16 ft./sec. In zones 14 and 15, air jets 19impinge upon the tobacco leaves and suction is established beneath belts17 and 18 by suitable means through conduits 20 and 21. It is to benoted that the air jets in 14 impinge on the leaves, preferably off thevertical in different directions (plus and minus). Desirable angles ofimpinge off the vertical are from about to 30 plus and minus. This aidsin the separation and the positioning of the leaves. By operating asdescribed, the tobacco leaves 30 which are loaded on vibrating belt 16will tend to separate as illustrated in the top view as shown in FIGURE2b. Thus, these conveyors 16, 17 and 18 moving progressively faster andvibrated as described cause the leaves to separate and thus permit theefficient removal of undesirable materials. The stream of air jets 19impinging on these leaves aid the leaves to further separate. Thus, inpassing through each of the different zones 13, 14, and 15, the leavesin zone will be positioned so that only a single leaf will occupy agiven position and no leaf will remain folded. In essence, the vibrationand air streams initiate the cleaning operation causing the foreignmatter to loosen and fall through the wire mesh for disposal. theconveyors in the vertical plane, it is to be understood the conveyorsmay also be concurrently vibrated in a horizontal plane.

The leaves, now positioned on the conveyor only as single units, pass tocleaning stage 11 and onto a vibrating belt 22. The linear velocity ofvibrating belt 22 is greater than the velocity of belt 18 as illustratedby the following formula: V =V +K V In stage 1, suction is applied bothabove and below the moving mesh screen by means of suction nozzles 23and 43. Suction is ap plied through these nozzles by conventional meansnot shown. The relative suction pressures of nozzles 23 and nozzles 43are so adjusted as to keep the respective lever tightly adhered to theconveyor 22. These vacuum suction conduits mounted above and below themoving leaves will pick-up loose foreign matter such as sand, feathers,rubber bands, string and the like and thus produce a clean leaf withoutdisturbing or distorting the alignment of the individual leaf on theconveyor. Another feature of the present invention is that the conveyorbelts are cleaned on the return cycle. This removes any foreign matterthat becomes entangled or enmeshed in the wire mesh which, if allowed toremain, would decrease the efficiency of the vacuum process.

Finally, the leaves pass into grading stage 12 and onto conveyor belt24. In grading zone 12, the clean tobacco leaves pass underphotoelectric cells 25, which cells are set in a conventional manner todetect different shades in the color and thus function to preferentiallyselect leaves of different hues and colors. These photoelectric cellsfunction through conventional relays and ancillary equipment whichactivate suction ports 26 so as to pick-up the various graded leaves ina predetermined pattern. It is to be understood that any number ofphotoelectric cells 25 and any number of suction pick-up nozzles 26 maybe used. If four grades are to be selected in addition to thepredominant grade, then four pick-up parts are used.

Under certain conditions, the final selection of two or more grades ispreferably accomplished manually by an operator. The tobacco leaves thatare not picked up and removed remain on the grading conveyor, are of onegrade and will constitute the majority of leaves of predominant gradefalling into a given grade of a single load or cure. These tobaccoleaves constituting the predominant grade will continue along theconveyor and will be deposited into a container at the end of the belt.All grades are then bundled and tied automatically from which operationthe bundles go to storage or are delivered directly to a purchaser ormarket.

While it is preferred to vibrate Thus, the function of the presentsystem and process is to produce clean and properly graded tobacco fromcured tobacco received from the producer or purchaser. This isaccomplished by an integrated plurality of processing steps which, inessence, comprise vibrating screens, preferably of different lengths andmoving at progressively higher speeds and tied in with ancillary suctionand pickup means.

It is to be noted that in the separation stage wherein it is desirableto position a single leaf at one spot on the conveyor 18, suction isonly applied to the underside of the screen, thereby permitting theleaves 30 to separate as illustrated in FIGURE 2b. This separation issecured by the cooperation of air jets preferably applied tangentiallyon the top of the leaves. In cleaning stage 11, on the other hand, afterthe leaves are secured or positioned at one spot on the screen, suctionis applied both above and below the screen, which effectively removesthe last traces of the undesirable contaminants.

Thus, the present invention is concerned with a unique integratedprocess for the effective cleaning of tobacco as it is delivered fromthe producer for the effective and rapid grading of the same and for theeffective tying, bundling or bailing of tobacco.

What is claimed is:

1. Improved apparatus for the removal of foreign materials from tobaccoleaves which comprises in combination a plurality of perforatedconveyors suitably mounted in a separation stage, means for verticallyvibrating said conveyors, suction means positioned below theintermediate conveyors, air jet means positioned above said intermediateconveyors whereby as the tobacco leaves pass from the initial conveyorto the secondary conveyor the leaves tend to space themselves one fromanother, suction means positioned above and below the final conveyorwhereby as the tobacco leaves pass between the same foreign materialsare removed, a plurality of photoelectric cells positioned in a gradingstage, which cells in response to varying shades of color of the tobaccoleaves activate pick-up means which pick-up the tobacco leaves of thedifferent shades and separate the same one from the other.

2. Apparatus as defined by claim 1 wherein means are provided wherebysaid intermediate conveyor-s have a higher velocity than said initialconveyor and said final conveyor has a higher velocity than saidintermediate conveyor.

3. Improved apparatus for the separation of foreign contaminants fromtobacco leaves which comprises in combination an initial, a secondaryand a tertiary perforated conveyor suitably mounted and positioned in aseparation zone, a fourth conveyor positioned in a cleaning zone, meansfor vibrating all conveyors, suction means positioned below saidsecondary and said tertiary conveyor, air jet means positioned abovesaid secondary and said tertiary conveyor, said jets so positioned as toimpinge air jets on the tobacco leaves as they pass thereunder, suctionmeans positioned above and below said fourth conveyor whereby as thetobacco leaves move from the initial to the fourth conveyor foreigncontaminants are removed therefrom, a plurality of photoelectric cellspositioned in a grading stage, which cells in response to varying shadesof color of the tobacco leaves activate pick-up means which pick-up thetobacco leaves of the different shades and separate the same one fromthe other.

4. The apparatus as defined by claim 3 wherein the respective conveyorsare positioned progressively lower as they move from said first to saidfourth conveyor.

5. Apparatus as defined by claim 4 wherein means are provided to movethe respective conveyors at progressively higher velocities from saidfirst to said third conveyor.

6. Apparatus as defined by claim 5 wherein the length of the conveyorbelts progressively decrease from said first to said third conveyor.

7. Process for the rem-oval of contaminants from tobacco leaves whichcomprises passing the tobacco leaf at a progressively higher rate ofspeed from one zone to another and subjecting the same to vibration,subjecting the underside of the tobacco leaf to suction in a secondaryand tertiary stage and impinging air jets on the top of the tobaccoleaves in said secondary and said tertiary stages whereby the tobaccoleaves tend to separate one from the other, thereafter subjecting thetobacco leaves on the top and underside to suction in a fourth stage,and thereafter passing the tobacco leaves beneath photoelectric cellgrading units whereby the different grades are picked up and graded asdesired.

References Cited by the Examiner 5 UNITED STATES PATENTS 10 M. HENSONWOOD, ]R., Primary Examiner.

1. IMPROVED APPARATUS FOR THE REMOVAL OF FOREIGN MATERAILS FROM TOBACCOLEAVES WHICH COMPRISES IN COMBINATION A PLURALITY OF PERFORATEDCONVEYORS SUITABLY MOUNTED IN A SEPARATION STAGE, MEANS FOR VERTICALLYVIBRATING SAID CONVEYOR, SUCTION MEANS POSITIONED BELOW THE INTERMEDIATECONVEYORS, AIR JET MEANS POSTIONED ABOVE SAID INTERMEDATE CONVEYORSWHEREBY AS THE TOBACCO LEAVES PASS FROM THE INITIAL CONVEYOR TO THESECONDARY CONVEYOR THE LEAVES TEND TO SPACE THEMSELVES ONE FROM ANOTHER,SUCTION MEANS POSITIONED ABOVE AND BELOW THE FINAL CONVEYOR WHEREBY